let a = 1;
let b = 2;

function jia(){
    console.log(a+b);
}
function jian(){
    console.log(b-a);
}
function cheng(){
    console.log(a*b);
}
function chu(){
    console.log(b/a);
}

module.exports = {
    jia : jia,
    jian : jian,
    cheng : cheng,
    chu : chu
}